Other Models of 4000 Series:
4000 ID1, 4000 ID2, 4000 ID3, 4000 ID4, 4000 IR1, 4000 IR2, 4000 IR3, 4000 IR4, 4019, 4028, 4029, 4035, 4037

You may consider buying IBM 4039 Remanufactured Toner Cartridges. Remanufactured cartridges are used cartridges that have worn out parts replaced with new ones. They provide same level of quility as new toner cartridges, but for lower price. Using remanufactured cartridges saves energy and raw materials that would otherwise be consumed by production of new cartridges.